Gotán

“Tango can be discussed, and we discuss it, but it encloses, as everything that is true, a secret…a French or Spanish composer who threads a tango, discovers, not without surprise, he has threaded something that our ears do not recognize, that our memory does not host, and that our body rejects it could be said that without the sunsets and evenings of Buenos Aires no tango can be made…and that this adventurous species has, however humble, its place on the universe” (Borges in Gomez, 2007/trans. A. Michalko).

Since the 1930s, musicologists and dance specialists have tried to reconstruct and “put some systematic order” into tango origins (Savigliano, 1995). The search for Argentinean tango’s beginnings and authenticity raised many discussions as some historians attribute it to African population connecting it to their rituals and music traditions; others seek its origins in the art of payadores (singers and guitar players from the inside of the country); and some in the arrival of European immigrants at the end of 19th century. The matter of which one of these groups is more entitled to tango will not be discussed here. Instead, I would like to explore and compare the style of two iconic tango orchestras: Orquesta de Francisco Canaro and Orquesta de Anibal Troilo. The orchestra of Canaro was active mostly between 1920-1940s and orchestra of Troilo after 1940s. One remarkable difference is that Canaro performed mostly with female singers whereas Troilo with male tangueros. I will analyze their dyscographies in order to find some other differences and similarities between them. Perhaps, this analyisis will reveal some secrets of tango.

Corpus

The Corpus consists of tango songs performed by orquesta de Canaroand Orquesta de Troilo. On basis of their dyscographies and recordings, I will search for similarities and differences between those two tango orchestras. The corpus consists of 608 tracks (304 performed by Orquesta de Canaro and 304 by de Orquesta de Troilo).

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Milonga

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The comparison of interdependencies among various audio features did not demonstrate that the recordings of two orchestras would follow individual/peculiar patterns. On contrary, in those three scatterplots, the orchestras seem to follow similar patterns. Perhaps, more detailed analysis of particular songs will reveal more differences between those tango orchestras. For instance, analysis of the same tango song.

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Both chromagrams illustrate tango song Silbando. The first is a version of Troilo orchestra and the second one of Canaro. The Spotify features clasify a key mode of both versions as D major. However, the A sections of the song are in d minor and B sections are in D major. Both chromagrams suggest a presence of rich harmony in two versions, especially chroma features of Canaro show a presence of almost all 12 tones throughout all the song (with exception of B and Bb). In Troilo’s version we can see better the predominance of A, G and D. It is not surprising as d/D is a Tonic, G/g a subdominant and A domimnant of d minor and D major.

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The original structure of the tango song Silbando is: Intro A A’ B B’ B’(whistling) A A’ B B’ B’(whistling). The versions of Troilo and Canaro vary substantially in structure, but also in the songs’ instrumentations. Silbando of Troilo has a structure of B B’ A A’ B’’ B’’’ A’’ A’’’ B’’’’ and has lots of timbre changes. Although, the piece was originally written for a singer and piano/orchestra, this version is instrumental. It starts with soft whistling accompanied by a guitar. In the next section clearly visible on the similarity matrix (around 25s) appears section B’, which is played on accordion and guitar. Interestingly enough, Troilo does not introduce a new instrument in each new section. Instead, he makes new combinations of the same instruments (for instance, accordion + guitar, guitar + double bass, accordion + double bass); manipulates acoustic balance between them (for instance, in B and B’‘we have the same combination of instruments, however, in B the accordion is much more salient than a guitar whereas in B’’ they are even); and changes timbre through the usage of various articulations (for, instance pizzicato and bowing on strings) and dynamics. For these reasons, the similarity matrix shows many timbre novelties (substantial amount of grey/yellow lines throughout the duration of all the piece), which in its turn indicate clearly the beginning of each section.

Nevertheless, the section division marked by the timbre novelties does not necessarily coincide with the general division of similarity matrix: , for instance the timbre novelty pattern suggests that the very beginning (0-25s) of Troilo’s version has two separate segments, although, it should be treated as one (A). On the other hand, the similarity matrix interprets the middle of the piece as a single section (from 60-120s), even though, it has many more sections within it (as indicated by the timbre novelty lines). We could interpret it as a Type I Error, even though, at this moment we are able to see the structure of the piece ( as we combine information from similarity matrix general segmentation and the timbre novelty lines). However, as the consequences of this error, the further analysis might yield incorrect results, for instance, of the key chord recognition.

The version of Canaro has a structure: A A’ B B’ A’’ A’’’ B’’ B’’’ B’’’’ A’’’’ A’’’’’. It is more difficult to see this structure on the similarity matrix as it does not have so many remarkable timbre changes as a version of Troilo. In fact, the entrance of the singer in 1:03 is almost not marked/visible on the similarity matrix. The big grey/yellow line around 2:10 signalizes a timbre novelty, which in this case is whistling.

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In the majority of tango songs, the Spotify features failed to assign a correct key to the song. It may be due to the fact that a new section of tango song is usually played in another key mode, for instance, the A part of Silbando is in d minor and the B part in D major. The chord recognition does not work very well either. The key mode of both performances of Silbando given by Spotify API features is D Major. Nevertheless, in case of orquesta de Canaro indicates in the first section a predominance of f# minor and c# minor. Around 80s a d minor comes into play, however, from 100s the f# minor and c# minor are again predominant. Two vertical yellow lines indicate transitions between sections A and B, which as mentioned before are in different modes (A in minor key and B in major key). Interestingly enough, these are not the only places where the transition between the modes takes place. It is rather clear that chord recognition failed to indicate major modes and in case of ambiguity ca 100s “privileges” minor modes.

In case of Troilo’s version the key chord recognition is also unprecise and ambiguous. Although, from 60s till 120s the algorithm distinguishes d minor, D Major, a minor and A Major, it is unable to point out the exact changes and transitions of the chords. It might be due to the incorrect section division (see similarity matrices) but the chord recognition made per bars yields similar results. It shows the simultaneous occurrence of A major and a minor, even though, the listeners are able to distinguish clearly a chord mode of each section and bar while listening to the piece.

These examples suggest that Spotify’s tools for harmony recognition are insufficient and unable to analyze/show a complexity and richness of tango harmony. In these cases, the difficulties and ambiguities in chord recognition stem from the tuning issues, segmentation ambiguities and confusion of partials.

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The comparison and analysis of timbre coefficents shows substantial differences between those two versions. The third component, which according to Spotify API correlates with spectral flatness has a very low values in Troilo’s version (from 5 till -120) and relatively high ones in Canaro’s version of this piece (from 40 till 80). It suggests that the spectral power, in case of Troilo’s performance, is concentrated in a relatively small number of bands whereas Cantro’s version has similar amount of power in all spectral bands. Furthermore, the difference in components 5, 6 and 7 is observed. Although, Spotify API does not specify with which acoustic features those components correlate, a possible candidates are: Log Spectral Spread and Roll- off, Spectral Irregularity or Spectral Entropy. However, which ones precisely still needs to be determined.

The individual cepstrograms of these two versions confirm the previous comparison.